Chbtstophee aitchison



(No Model.)

'0. AITOHISON.

BEATING ENGINE.

No. 387,840. Patented Aug. 14, 1888.

elm-var. or WM N4 PETERS. Phcmumc n nu. Washinglom n.c.

UNITED STATES PATENT Urrica.

CHRISTOPHER ATTOHISON, OF LOANHEAD, COUNTY OF hilD-LOTHIAN, SCOTLAND.

BEATlNG-ENGlNE.

SPECIFICATION forming part of Letters Patent No. 387,840, dated August14, 1888.

Application filed September 10, 1857. Serial No. 249,322.

To all whom it may concern:

Be it known that 1, CHRISTOPHER AITCHI- SON, 0f Loanhead, in the countyof Mid-Lothian, Scotland,have invented certain new and usefulImprovements in Beating-Engines; and I do hereby declare the followingto be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which it appertains to make anduse the same.

My invention (which has been patented in lreat Britain, May S, 1883, No.5,381) relates to that class of machinery used for the manufacture ofpaper-pulp, known as washing, breaking, and beating engines, and hasspecial reference to an improved construction and arrangement of thecutting-rolls and fixed knives or bed-plates of such machines, theobjcct of which is to secure more even or regular action of the kniveson the pulp.

In ordinary heating-engines for the manufacture and preparation of paperthe roll is made in the form of a cylinder, and is conseqnentl y ofequal diameter over all parts of the surface. The bed-plate,fixed underthe rol1,is laid on a level, is of equal width, and has an equal numberof knives or cutting bars throughout. Owing to the form of the roll, thepulp travels at the same speed under all parts of its surface, and overthe bed-plate it traverses the same extent of cutting-surface, whethercirculating near the mid-feather or central portion of the trough or vatcontaining the pulp or at its circumference; but the contents of thetrough nearest the midfeather have a much shorter distance to travelthan the contents nearest the circumference,pass more frequently betweenthe roll and bedplate, and are thus unduly broken up or ground beforethe outer orbit of pulp has been sufficiently acted upon. The bed-plateis inclinedcorrespondingly to the taper of the roll, and the breast andback fall of the trough are made to suit the form and position of thebed-plate and roll.

In the accompanying drawings similar let ters refer to similar partsthroughout the several views.

Figures 1 and 2 are respectively a plan and an elevation of the improvedpulpbeating engine. Fig. 3 is a transverse vertical section (No model.)Patented in England May 8, [883, No. 5,381.

showing the construction of the conical cutting-roll and bed-plate.Figs. 4 and 5 are plans of knife-plates adapted for use with the conicalroll. Fig. 6 is a plan of the box in which the knife-plates are fitted.It is not of precisely the same shape as said plates, for they need notexactly fill the box.

The improved engine comprises the usual trough or vat, A, formed with acentral partition or mid-feather, A, around which the pulp materialwhich is placed in the vat circulates. The cutting-roll Bis fitted inthe ordinary way in one of the divisions of the vat A, and is carried bya spindle, B, supported in bearings 13 fitted in the sides of the troughor vat, the spindle being driven by a pulley, B, and belt. Thecutting-roll Bis made of slightly tapering or conical form, the outerend being of greater diameter than the end next the mid-feather A, andthe knives b are fixed longitudinally in the usual way. The knifeplate 0is formed of ordinary cutting knives or blades, 0, which are made toincrease in number from the inner to the outer end. A number of knives care fitted parallel to each other, and short lengths of additionalknives are fitted in the outer end of the knife-plate to give a greaterbreadth of cutting-surface under the outer end of the tapered cuttingroll. As shown in Fig. 4, the long knives are bent near their outercnds,and the short knives are parallel to the shorter parts of theselong bent knives. As shown in Fig. 5, all the knives are straight andparallel to each other. Either of these constructions may be used, aspreferred.

Theknife-plate Gis fitted in abox, G, which is fitted to slide, asusual, through an opening in the side of the vat A. The box (3 rests onan inclined seat, so that the cutting surface or edges of the knives care in planes parallel to those of the knives b of the roll, as shown inFig. 3. The ordinary device for adjusting the roll B vertically is used.

The pulp traveling around the outer wall of the vat A passes overalarger cutting-surface on the bed-plate C than does the pulpcirculating near the mid-feather. Compensation is thus provided for theless frequent passage under the roll B and over the bedplate 0 of thepulp traveling near the outer side of the vat A. Owing to the taperingshape of the roll B, a thorough mixture and interchange of the pulp iseffected. It is also drawn under the knives c sooner at the wider end ofthe bed-plate C, and is delivered with greater velocity over the backfall, E, and

around the circumference of the vat A,where it should travel withgreatest speed, and the entire contents of the vat A are made tocirculate more rapidly. The pulp is thus more regularly and efficientlyacted upon and in much shorter time than in an engine of the ordinaryconstruction, and produces a much better result.

WVhile I describe but one roll and one knifeplate, I can use two rollsand two knife-plates in the same vat, if desired.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent of the United States of America, is-

1. The vat A and mid-feather A, in combiting-surface at the end of thebox which is 5 under the larger end of the conical roll, substantiallyas set forth.

In testimony whereof I have hereunto subscribed my name in the presenceof two subscribing witnesses.

GHRISTOPHER AITOHISON.

Witnesses:

HUGH G. PEAOOOK, N. B. BROWNLEE.

